Time lag interlock



OC- 10, 1939. J, w. coNKLlN TIME LAG INTERLOCK Filed DeO. 20, 1934 l i S70 SIHZY INVENTOR. JAMES W. CONKLIN ATTORNEY.

Patented Oct. 10, 1939 UNITED STATES PATENT OFFICE TIME LAG INTERLO CKtion of Delaware Application December 20, 1934, Serial No. 758,408

8 Claims.

This invention relates to a time lag interlocking relay switch. Anobject of this invention is to provide a simplified and improved timelag relay switch which will be cheaper to manufacture,

rugged in construction and yet maintain a fairly accurate control.

Another object of this invention is to improve the time control of aninterlocking relay switch as is used in the circuit of a hot cathoderectier tube used in a radio transmitter which would make it impossibleto apply plate current to the rectifier tube until the filament has beensufficiently heated.

Another object of this invention is to overcome the defects in existingtime lag relay switches wherein vibrations cause the switches to eitheroperate at the right time, or fail to operate at such times as it isdesired to be in an operative position. Such vibrations may be of amechanical origin or may be due to magnetism caused by the closeproximity of associated magnetic materials.

A feature of this invention is that the time of the interlocking relayswitch is governed by design of a heating coil which can be regulatedaccurately by properly controlling the heating current.

Another feature of this invention is the mechanical arrangementincorporating the toggle link release principle, which has a minimumamount of friction and always exerts the same mechanical force againstthe thermostat element, thus providing an arrangement wherebyconsiderable force can thus be positively looked and likewise releasedWithout much effort.

Another feature of this invention is the use of a bimetallic striphaving a heating coil which entirely surrounds the bimetallic strip.

In the present-day use of hot cathode rectiers of the mercury vaportype, it is necessary to prevent the application of plate current beforethe filaments have been sufficiently heated or reached the properoperating temperature. Therefore, in order to prevent such anoccurrence, I have conceived this improved type of time lag 45interlocking relay switch which acts as an auxiliary switch to the maintransmitter contactor or multi-actuated switches, at least one of saidswitches being arranged to make and break the plate circuit of thetransmitter tube or tubes.

This invention will best be understood by referring to the accompanyingdrawing in which Fig. 1 shows a front elevation of improved time lagrelay switch. Fig. 2 is a sectional view of Fig. 1. Fig. 3 shows anelementary wiring diagram of the time lag interlocking switch.

Referring now in detail to Figs. 1 and 2, I represents a base ofinsulation material having the necessary requisite insulating qualitiesto withstand the voltage through which this device is to be used inoperation. Element 2 is a bimetallic strip which comprises thethermostatic or time lag element, which is arranged so that the materialbends in the direction of the arrow 3 when sufficiently heated to givethe desired time lag. A heating coil 4 is wound around the bimetallicstrip and insulated therefrom by suitable insulation material 4a for thepurpose of heating the strip to control the time lag in which thisswitch operates. 5 is a mechanical actuating button which is securelyfastened to the bimetallic strip 2 at a position just above the heatingcoil 4. The bimetallic strip is supported by a base-like member S whichis fastened to the main linkage support l'. Element 8 represents anadjustable support and stop element which is arranged to maintain theactuating button 5 and bimetallic strip 2 in a desired positiveoperating position, which position is such that any tendency to be upsetby vibrations, etc., will be overcome. The contact relationship betweenmember 8 and button 5 should be adjusted to a position which willrequire but a minimum force of a few ounces to set the actuating buttonin motion to open or close the groups of auxiliary contacts. The upperend of heating coil 4 is connected through the panel by an extendingstud 9, the lower end being fastened by a screw I0 to make electricalconnection to the supports 6 and "I, the connection through the panelbeing made by the stud-like member II. Pivotally located on the supportmember 'I is an adjustable link I 2 of a toggle link system which is ofmetal or other suitable material. The upper portion of the adjustablelink l2 is provided with a strip of insulating material I3 on which themechanical Contact button 5 bears in a position which is such that thepivot point between links I2 and I3 is slightly olf dead center, andarranged to operate the upper portion of the linkage system when thebimetallic strip 2 is sufficiently heated and bends to cause the togglelink system to snap past the dead center position.

To the insulating member I3 there is fastened an L-shaped link memberI4, which is pivotally secured to the panel by a support stud I5. Thelower portion of member I4 carries an auxiliary or heater Contact springI6 which may be slightly bowed away from member I4 and is provided atits upper portion with a movable contact Il. The amount of curvature ofthe bowed part of spring it is about one-quarter of the total movementof members i111 at the point of contact of members 26, 2i and 22, Themovable contact H in the position shown makes Contact with a xed Contacti8 which is secured to the base l by a stud i9. The extreme upperportion of member ill carries a plate circuit contact 2E? which makescontact with a contact 2l which is fastened to the spring-like member 22secured to panel I by means of a bolt 23, Electrical connection is madeto the auxiliary or heatel1 contact spring I6 by means of a iiexiblelead 24 which is secured to the support panel i by a bolt 25. Directlybelow the plate circuit contacts 2i) and 2| there is pivotally securedto the member Id a rod-like link 2G, and secured thereto is an uprightoperating lever 27 which is actuated by the movement of a main radiotransmitter line switch or magnetic contactor A or other suitablecontrol motion which may comprise an electro-magnetic coil B, anarmature C and a plurality of switch blades D. Contacter A moves themember 2l radially, either to the left or the right as indicated by thedotted lines. Between member 2l and member M there is provided a shortcoil spring 28, and on the other side ci member 2l there is provided along coil spring which is securely fastened to the rod by a washer 32and cotter-pin 3l. A reset spring is fastened to the lower end ofsupport l' by means of the screws 33 and is always in frictionalengagement with the link l2 at a point 34.

In the operation of this interlocking time lag relay, when thetransmitter main control or multi-switch contactor A is actuated byenergization of magnet B, armature C is moved inward toward panel i, andcarries with it in addition to the switch blades D the depending lever2l, and as member 2l is pivoted at point E, it moves outward and triesto pull the rod-like member 26 along with it, but is only .able at thistime to cornpress the long coil spring 29, as forward movement of rod.'ii is prevented by the position of links l2 and i3. The resultantforce which is transmitted through the lever lli puts links l 2 and i3in compression, they being held out of the vertical line position by thereset spring 32, and are forced against the actuating button 5 which issecured to the bi-metallic thermostatic element 2, and thus preventedfrom moving forward at this time. Simultaneously with the above and bymeans oi contacts il and i8 being closed, the transmitter vacuum tubeheating current which may or may not be supplied through contacts D orother auxiliary contacts, such as switch lili, passes through a heatingcoil Il. The circuit .arrangement of the filament heating current andits relationship with switch lli, is shown in Fig. 3. It will be notedthat switch itl has leads 36 and 3@ connected in parallel therewith, sothat when the supply current is connected to the filaments by means ofswitch S and switch 40 is closed, current passes through the bi-metallicheating coil through leads il and contacts l'i and it. When thebi-metallic strip is sufciently heated to give the desired time delay,the internal forces set up against the bi-metallic strip will cause itto bend and move outward against link i3, forcing both links i2 and i3outward and past 'the dead center position. As soon as members l2, itand ifi have moved past the vertical line oi their dead center position,the system will then not be in equilibrium, and links I2 and i3 willquickly snap forward to the position indicated by the dotted lines,carrying with them member I4 and rod 26. At this time, contacts 2li and2l will be closed, asy a result of the position assumed by member I4,and held closed by spring 29. Also, auxiliary bi-metallic strip heatercontacts l'l' and I8 will open, thus opening the bimetallic strip heatercircuit and allowing bimetallic strip 2 to cool sufliciently, thusreturning to the normal position shown. The contacts 2) and 2l will beheld securely closed by spring 25J until such time as the main contactorA is released. When main line contactor A or any other suitable controlmotion is reversed in operation by a release of energy in magnet B,spring 28 acts upon the system to force member ifi back to its normalposition and the toggle links i2 and i5 are then reset to again bearagainst button 5 by the spring member 32.

Referring to the schematic wiring diagram, Fig. 3, the auxiliary orplate circuit is represented by the lines 35 and 31. The heater circuitis indicated by lines 38 and 39, and is connected in series with theplate switch dii, which may be one of the contactors of the maincontactor A. The switch li is connected to the stud le supporting thexed contact I8, an electrical circuit connection is made to contact Ilby way of spring iii. The position of contacts Il and it is governed bythe operation of the toggle link system, as explained above. Theflexible lead 2li connects the heating circuit to the support member lby a bus 4i; the heating coil Ll connects from the member l to thestud-like member 9, which is connected in the rear to line 39.

It will be apparent that this invention is not limited to the particularconstruction which is illustrated by the drawing and herein described,as itis capable of various other modifications without departing fromthe spirit of invention, as set forth in the appended claims.

I claim:

l. A time lag interlocking switch coupled to a main contactor having aplurality of contacts, said switch comprising a bimetallic strip, agroup of auxiliary contacts linked to said main contactor, at least onecontact of said group of auxiliary contacts being mounted on a movablemember having means for actuating said movable member by an adjustablelink forming one element of a linkage system linking said auxiliarycontacts with said main contactor and arranged with said bimetallicstrip to actuate said group of auxiliary t contacts, a heating elementsurrounding said bimetallic strip to supply heat thereto, the heatcausing said bimetallic strip to move and actuate the contact on saidmovable member when said bimetallic strip reaches a predeterminedtemperature.

2. A time lag interlocking switch coupled to a main contactor having aplurality ci contacts, said switch comprising a bimetallic strip, agroup of auxiliary contacts linked to said main contactor, at least onecontact of said group of auxiliary contacts being mounted upon a movablemember having means for actuating said movable member, an adjustablelink forming a toggle release system linked to said main contactor andarranged with said bimetallic strip to actuate a pair of contacts, aheating element surrounding said bimetallic strip to supply heatthereto, the heat causing said bimetallic strip to move said togglerelease system and actuate the contact on said movable member when saidbimetallic strip reaches a predetermined temperature after movement ofsaid main contactor.

3. A time lag interlocking switch coupled to a main contactor having aplurality of contacts,

said switch comprising a bimetallic strip, a group of auxiliarycontacts, at least one contact of said group of said auxiliary contactsbeing mounted on a movable member, means for actuating said movablemember by an adjustable link forming a toggle release system linkingsaid auxiliary contacts with said main contactor, a plurality of springsarranged with said release system so as to actuate said group ofauxiliary contacts, a heating element surrounding said bimetallic stripto supply heat thereto, the heat causing said bimetallic strip toactuate the contact on said movable member when said bimetallic stripreaches a predetermined temperature.

4. A time lag interlocking switch coupled to a main contactor having aplurality of contacts, said switch comprising an arm extending out fromsaid main contactor, a link member carrying auxiliary contacts coupledto said arm, a time delay release system coupled to said link member toactuate said auxiliary contacts after a predetermined time has elapsedfollowing the movement of said main contactor, said time delay releasesystem comprising a toggle-like arrangement, a bimetallic strip having amember bearing against said toggle-like arrangement, a heating coilsurrounding said bimetallic strip to heat said strip sufficiently tomove said toggle link when said predetermined time has elapsed aftermovement of said main contactor.

5. A time lag interlocking switch coupled to a main contactor having aplurality of contacts, said switch comprising an arm extending out fromsaid main contactor, a link member carrying auxiliary contacts coupledto said arm, a time delay release system coupled to said link member toactuate said auxiliary contacts after a predetermined time has elapsedfollowing the movement of said main contactor, said time delay releasesystem comprising a toggle-like arrangement, a bimetallic strip having amember bearing against said toggle-like arrangement, a heating coilsurrounding said bimetallic strip to heat said strip sufficiently tomove said toggle link when said predetermined time has elapsed aftermovement of said main contactor, and a reset spring bearing against saidtoggle-link arrangement to reset said auxiliary contacts.

6. A time lag interlocking switch which is mechanically coupled to adevice for controlling motion comprising a bimetallic strip, a group ofcontacts, at least one contact of said group of contacts being mountedupon a movable member, means for actuating said movable member by anadjustable link forming a toggle link release system linking said devicefor controlling motion With said group of contacts, a. plurality ofsprings arranged with said link release system to actuate said group ofcontacts, a heating element surrounding said bimetallic strip to supplyheat thereto, the heat causing said bimetallic strip to move and allowone of said springs to actuate the contact on said movable member whensaid bimetallic strip reaches a predetermined temperature, and means toadjust said bimetallic strip to alter the position thereof with respectto said toggle link release system.

7 A time lag interlocking switch which is mechanically coupled to adevice for controlling motion comprising a base member having three linkmembers secured to said base, the rst of said link members being coupledto said device for controlling motion, the second of said link memberscoupled to said iirst link member, a pair of contacts located on eachside of said second link, and an adjustable toggle link release systemiorming the third link which is coupled to said second link member, saidsecond link coupled to said iirst link member, a bimetallic strip havingmeans to actuate said adjustable toggle release system, a heatingelement surrounding said bimetallic strip to supply heat thereto forreleasing said toggle link system and to actuate said contacts when saidbimetallic strip reaches a predetermined temperature.

8. A time lag interlocking switch which is mechanically coupled to amain contactor having a plurality of contacts, said switch comprising agroup of auxiliary contacts, at least one of said group of contactsbeing mounted upon a movable member and having means for actuating saidmovable member by a bimetallic strip, an adjustable threaded link memberforming a toggle link release system linking said main contactor withsaid group of auxiliary contacts and arranged with said bimetallic stripto actuate a pair of said auxiliary contacts, a heating elementsurrounding said bimetallic strip to supply heat thereto and to movesaid link release system to actuate the auxiliary contacts on saidmovable member when said bimetallic strip reaches a predeterminedtemperature.

J. W. CONKLIN.

